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Reconstitution of human MCF-7 breast cancer cells with caspase-3 does not sensitize them to action of CDK inhibitors.
MedLine Citation:
PMID:  21080333     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Human MCF-7 breast cancer cells are resistant to pro-apoptotic stimuli due to caspase-3 inactivation. On the other hand, they should be sensitive to agents like selective pharmacological inhibitors of cyclin-dependent kinases (CDKs) that (re)activate p53 tumor suppressor protein because they harbor intact p53 pathways. In this study we examined whether reconstitution of caspase-3 in MCF-7 cells sensitizes them to inhibitors of CDKs, by analyzing the effects of roscovitine (ROSC) and olomoucine (OLO), two closely related selective pharmacological CDK inhibitors, on both mother MCF-7 cells and a secondary mutant line, MCF-7.3.28 that stably expresses human caspase-3. The results show that ROSC is, as expected, much more potent than OLO. Surprisingly; however, ROSC and OLO reduced proliferation of parental MCF-7 cells more strongly than caspase-3-proficient counterparts. Both inhibitors arrest human breast cancer cells at the G(2)-phase of the cell cycle. Analysis of cell-cycle regulators by immunoblotting revealed that ROSC strongly induces p53 protein activity by inducing its phosphorylation at Ser46 in the MCF-7 cells lacking caspase-3, but not in caspase-3-proficient cells. Furthermore, reconstitution of caspase-3 in MCF-7 cells neither elevates the mitochondrial apoptosis rate nor significantly increases caspases activity upon ROSC treatment. However, the stabilization of p53 in response to DNA damaging agents is the same in both caspase negative and positive MCF-7 cells. Cytotoxic agents induce caspase-3-dependent apoptosis in caspase-3-proficient cells. These results indicate that reconstitution of MCF-7 cancer cells with caspase-3 sensitize them to the action of DNA damaging agents but not to ATP-like pharmacological inhibitors of CDKs.
Authors:
Józefa Węsierska-Gądek; Stefan Hackl; Nora Zulehner; Margarita Maurer; Oxana Komina
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cellular biochemistry     Volume:  112     ISSN:  1097-4644     ISO Abbreviation:  J. Cell. Biochem.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-12-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8205768     Medline TA:  J Cell Biochem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  273-88     Citation Subset:  IM    
Affiliation:
Dept. of Medicine I, Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria. jozefa.gadek-wesierski@meduniwien.ac.at
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